RFID (Radio-frequency identification) applications sometimes require the ability to detect location of an RFID tag object on an RFID reader surface. To solve this requirement, as an example, typically an HF (High frequency) RFID reader uses multiple antennas, where each single antenna has the function of both RF (Radio-frequency) Field & Data transmission and Data reception to/from the HF RFID tag object. For example, if a user wants to detect an HF RFID tag object on 10 different surface locations, then 10 Transmission/Reception antennas are used, where each antenna represents one physical location. Switching Transmission antennas is rather complex due to the high voltage conditions on the antenna coil and requirement to stay perfectly tuned to a given frequency, such as 13.56 MHz, to ensure best energy transfer. HF RFID tag objects can be powered as long as the antenna is active. Once the system switches to another antenna, then the HF RFID tag object on a previous antenna loses power (i.e., is being deactivated). As a consequence of instant switching of the Transmission antenna, the detection loop is slow since it has to reactivate the HF RFID tag object every time the antenna is switched on. Furthermore, it prevents constant energy harvesting from the RF field of the reader.
Therefore, it is desirable to have devices and methods that can overcome the following list of challenges:
1. Switching of Tx/Rx (Transmission/Reception) antenna under high voltage conditions
2. Slow detection loop due to reactivation of HF RFID tag object after each antenna switch
3. Interrupted energy harvesting